[gumby79]

Hydrogen Fuel Injection a Green Upgrade for Thirsty Semi Trucks
For those that are "hho is and will always be a unicorn "

Non-hydrogen injected semi-trucks average between 5 to 6 mpg, whereas the Intel-branded hydrogen trucks average around 6.3 mpg. During a recent trip through California, an Intel hydrogen truck averaged 7.2 mpg representing a significant carbon footprint reduction.

I had a '79 K-20 (3/4t 4×4) with proformance parts Edelbrock carb stock air cleaner with heat riser and a PVC ... ennd of list for smog equipment... I worked at a gas station that had a smog test station. The boss wanted to do an experiment.. High power tune minimal (but leagal except carburetor. ) the truck was running at the bottom of the accepted emissions range. Then we threw all the BS required for a 1/2t CA. Truck (a list of like 20 items) on the engine and then it could pass the visual inspection but the Co and HC were a fail. this was before the NOx dino load cell test..
Summary
A rebuild. 030 over 9.75:1 1979 CARB (California air resources board) compliant 350ci runs dirtier than a hopped up tuned engine...... So we went back to the 1979 Federal, Heavy Duity(over 8501lbs GVWR) emissions equipment list stated previously (3 item list)and a tuned McM Quadra jet (795cfm used on 305ci-454ci) for a clean pass for registration. Then we cleaned up the emissions more by going back to the 1406 Edelbrock carb (600cfm) with the short list.
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A way around the GROSS POLLUTER in the future (your RV is already branded GP so this dusn't help you but it will help others ) ...If your questionable do a "pretest" (the results are not sent to CARB) if it passes then apply the test to a Smog Certificate. If it dusen't pass then you save money and your rig is not reported as a GP .
The timing may have to be adjusted outside of parameters to keep the NOx under control.
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is your Toyota tested on a Dino? if not dont worry about NOx its been a decade since I had to dill with CARB (as the NOx test was coming alive. But NOx could only be measured "under load" aka on a dino/load cell . This exempted all fulltime 4wd (Subaru, certain 4×4 trucks ) and over sized vehicles RVs and such from NOx part of the test.
Check and clean your EGR if its sticky it causes problems
Hope this helps
Gumby Stay Flexible